In an industry that is constantly evolving, thin-film solar panels are an exciting and innovative product that can be used to efficiently convert sunlight into electricity.
Unlike the traditional, rigid monocrystalline or polycrystalline photovoltaic (PV) solar panels you may be used to seeing, thin-film solar cells are, well, thin and flexible.
Suitable for many unique applications, thin-film panels can be used to generate electricity in a variety of instances in which a traditional type of solar panel may be less effective.
To help you understand the pros, cons, strengths, and weaknesses of thin-film solar panels, let’s explore how they work and dive into some of the most exciting aspects of this emerging technology.
Definition of Thin-Film Solar
Thin-film solar panels harness energy from direct sunlight using one or more thin layers, or a thin film of semiconducting materials placed on a suitable base such as glass, plastic, or metal.
For an example that you are probably familiar with, solar-powered calculators are one of the most widely established applications for thin-film cells.
Thin-film solar cells can be made of a variety of materials, including popular compounds such as:
- Cadmium Telluride (CdTe)
- Copper Indium Gallium Diselenide (CuInSe2)
- Amorphous Silicon (a-Si)
- Gallium Arsenide
While thin-film solar products have been around for decades, the technology is advancing rapidly, with new ideas constantly being tested and improved. In early 2022, researchers at the University of Surrey successfully increased the energy absorption levels in a thin-film solar panel by 25%, achieving a new record of 21% efficiency.
Differences Between Thin-Film Solar Panels and Standard Silicon Solar Panels
The key differences between thin-film solar panels and standard silicon solar panels are their size, strength, and cost. Unlike bulky, rigid silicon solar panels, thin-film panels are as slim as a piece of paper, cheaper to produce, ship, and install, and can be flexible enough to mount on curved surfaces.
Today, traditional monocrystalline and polycrystalline photovoltaic (PV) solar panels are typically more efficient and durable than their thin-film counterparts. With less efficiency, a larger surface area may be required for thin-film cells to convert the same amount of sunlight into electricity as with standard silicon solar panels.
Still, as a lighter and cheaper option to produce and transport, continuous advancements in thin-film solar cells have allowed the technology to witness widespread adoption and a bright future ahead.
The Primary Thin-Film Solar Cell Materials
Ready to get technical? Here is a detailed look at the four main materials used in thin-film solar panels today:
Amorphous Silicon (a-Si) Solar Panels
As the first commercially available thin-film solar cell, Amorphous Silicon (a-Si) strips have been used since the late 1970s. Unlike the crystalline silicon wafers used in rigid panels, Amorphous Silicon cells generally have low efficiency levels but still perform well in a variety of light intensities.
Amorphous Silicon solar panels are made by depositing a layer of amorphous silicon onto a glass surface using chemical vapor deposition (CVD). The resulting material has a low thermal conductivity, which means it can absorb more heat than traditional crystalline silicon photovoltaic cells without overheating.
While cheap to manufacture and produce, a-Si panels tend to degrade more quickly than other types of thin-film solar panels, and have difficulty operating at temperatures below freezing.
Copper Indium Gallium Selenide (CIGS) Solar Panels
As one of the most popular thin-film technologies, CIGS solar cells use a series of copper, indium, gallium, and selenide layers to capture sunlight and generate electricity. CIGS panels utilize a multi-step process to collect and separate electrical charges, resulting in high-efficiency power production.
Suitable for building integration and several different flexible applications, CIGS research has created modules with thin-film solar panel efficiency levels up to 23% and rising, comparable to traditional solar panels. However, integrating copper, gallium, indium, and diselenide into one simple manufacturing process has made commercial production of the technology more difficult and expensive than other thin-film cells.
Cadmium Telluride (CdTe) Solar Panels
Second only to CIGS in popularity, cadmium telluride (CdTe) solar panels are another thin-film technology that has gained momentum in the last decade. Known for its quick and inexpensive development process, cadmium telluride solar panels have achieved similar efficiencies as traditional silicon solar panels, with reduced costs of production.
Flexible and ultra-thin, CdTe panels are among the most researched and tested technologies in new solar generation. However, the toxicity of the materials in CdTe solar panels has raised some environmental concerns.
Gallium Arsenide (GaAs) Solar Panels
With up to 40% efficiency in testing environments, Gallium Arsenide (GaAs) solar cells are another longstanding technology that is used in thin-film panels. Utilizing strong electric and heat resistant properties, GaAs solar panels have higher electron mobility than conventional silicon modules.
Tested and used in solar cars both on earth and in space (like the Mars Rover), GaAs solar cells are most applicable for high-power instances. While more expensive to produce than other thin-film technologies, GaAs solar cells continue to innovate and push the boundaries of renewable energy potential.
Advantages and Disadvantages of Thin-Film Solar Panels
Compared to traditional silicon solar collectors, thin-film solar panels come with a few distinct advantages and disadvantages.
Advantages of Thin-Film Solar Panels
- Lower Cost: Thin-film solar panels are generally cheaper to manufacture than traditional modules.
- Lighter Weight: Without any bulky or rigid parts, thin-film solar panels are easier to transport and install on a variety of surfaces.
- More Flexible: With flexible arrays, thin-film solar panels can be installed on curved buildings, boats, walls, and more.
- Less Invasive: Unlike bulky silicon panels, some people consider thin-film panels less invasive and more visually appealing than large photovoltaic arrays.
Disadvantages of Thin-Film Solar Panels
- Less Efficiency: Generally less efficient than traditional panels, thin-film installations require more space to produce the same amount of electricity.
- Reduced Durability: Built for flexibility, thin-film solar panels may be more prone to cracks, breaks, and malfunctions from weather conditions like rain or snow.
- Newer Technology: The testing, manufacturing, and real-world applications of thin-film solar cells are still very limited compared to rigid PV panels.
Best Thin-Film Solar Manufacturers
As one of the fastest-growing sectors of the renewable energy industry, there are many leading manufacturers currently pursuing thin-film solar products. While formerly leading companies like Solar Frontier have moved away from the space, there are still many thin-film solar companies to watch in the coming years:
- Hanergy: Hanergy is one of the largest solar manufacturers in the world, and specializes in thin-film solar panels. With six R&D centers in Beijing, Sichuan, Silicon Valley, and Uppsala, Sweden, Hanergy has made significant investments in thin-film solar cell research, resulting in almost 1,000 patents in new energy, including copper indium gallium selenide (CIGS) technology that has reached 21% efficiency.
- Renogy: With a wide range of flexible solar products, Renongy is a consumer-facing company for small-scale electricity production. Today, their thin-film solar panels can be purchased one by one, or at wholesale rates for large installations.
- SunPower: As one of the largest solar panel manufacturers in the world, SunPower's flexible solar panels are portable, flexible, and backed by a thick, weather-resistant copper foundation. The California-based company currently sells thin-film solar panels primarily for use on the go in RVs and other small applications.
Exciting Developments in Thin-Film Solar Panels
With a strong foundation powered by decades of research and development, thin-film solar cells are among the most exciting and innovative technologies driving the future of solar power. While we may still be simply scratching the surface of their full potential, here are a few interesting advancements to look out for in the near future:
- Researchers at Stanford & Oxford University have developed a new type of solar cell that uses organic molecules called perovskite solar cells, which may be cheaper and easier to produce than traditional silicon-based cells.
- Similarly, researchers are developing a working perovskite “solar paint” which can be sprayed, printed, or dyed onto a surface to conduct electricity.
- The future is also bright for thin-film building-integrated photovoltaics, such as transparent solar panels and solar shingles. In both residential and commercial applications, these technologies can bring the electricity generation of thin-film solar into the functional elements of a building.
- Looking out even further, the success of thin-film solar panels in space makes the lightweight and highly efficient technology a key element in further galaxy exploration.
Should you get thin-film solar panels for your home’s roof?
Thin-film solar panels are currently most often utilized on commercial buildings where ample space is available since many residential roofs are limited in total surface area. With that said, technological advancements are continuing to push the efficiency of thin-film panels forward, and residential applications are slowly becoming more cost-effective.
There are many pros and cons of buying flexible solar panels and the choice to use thin-film cells should be weighed on a case-by-case basis.
The Future of Thin-Film Solar Panels
With versatility and ease of use, thin-film solar panels are among the most exciting developments in the solar industry. As the technology continues to advance, thin-film solar cells are being used in many practical applications, beyond just rooftop power generation.
If you’re considering a solar panel installation of any kind, you can talk to Palmetto to learn more about your options. With our Free Solar Design and Savings Estimate tool, you can instantly see how much you can save with solar energy.